Mass spectrometric characterization and physiological actions of novel crustacean C-type allatostatins.

Abstract

The crustacean stomatogastric ganglion (STG) is modulated by numerous neuropeptides that are released locally in the neuropil or that reach the STG as neurohormones. Using 1,5-diaminonaphthalene (DAN) as a reductive screening matrix for matrix-assisted laser desorption/ionization (MALDI) mass spectrometric profiling of disulfide bond-containing C-type allatostatin peptides followed by electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) tandem mass spectrometric (MS/MS) analysis, we identified and sequenced a novel C-type allatostatin peptide (CbAST-C1), pQIRYHQCYFNPISCF-COOH, present in the pericardial organs of the crab, Cancer borealis. Another C-type allatostatin (CbAST-C2), SYWKQCAFNAVSCFamide, was discovered using the expressed sequence tag (EST) database search strategy in both C. borealis and the lobster, Homarus americanus, and further confirmed with de novo sequencing using ESI-Q-TOF tandem MS. Electrophysiological experiments demonstrated that both CbAST-C1 and CbAST-C2 inhibited the frequency of the pyloric rhythm of the STG, in a state-dependent manner. At 10(-6)M, both peptides were only modestly effective when initial frequencies of the pyloric rhythm were >0.8Hz, but almost completely suppressed the pyloric rhythm when applied to preparations with starting frequencies <0.7Hz. Surprisingly, these state-dependent actions are similar to those of the structurally unrelated allatostatin A and allatostatin B families of peptides.

• Authors: Mingming Ma, Theresa M Szabo, Chenxi Jia, Eve Marder, Lingjun Li
• Journal: Peptides (Peptides) Vol. 30 Issue 9 Pg. 1660-8 (Sep 2009) ISSN: 1873-5169 [Electronic] United States
• PMID: 19505516 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Neuropeptides

Topics

• Action Potentials (drug effects, physiology)
• Amino Acid Sequence
• Animal Structures (chemistry)
• Animals
• Brachyura (chemistry)
• Brain Chemistry
• Crustacea (chemistry)
• Databases, Protein
• Dose-Response Relationship, Drug
• Ganglia (chemistry, drug effects, physiology)
• Mass Spectrometry
• Molecular Sequence Data
• Nephropidae (chemistry)
• Neurons (drug effects, physiology)
• Neuropeptides (analysis, chemistry, pharmacology)
• Pylorus (drug effects, innervation, physiology)
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• Tandem Mass Spectrometry